Shellfish is a culinary term that is often used for several species of molluscs, gastropods, bivalves and arthropods. Some examples are the St. James shell, mussels, razor clams, oysters, cockles and whelks. Most shellfish live partly or fully buried into the seabed, mostly in sandy or gravelly bottoms. They feed by filtering nutrients out of the water. Seed and eggs are released into the water and fertilized externally. Most shellfish are hermaphroditic, they can be both male and female. There are many different shellfish species in the North Sea that are very much suitable for consumption. Fishing methods on shellfish include hand-picking, dredging or mechanic dredges (suckers).
The Manilla clam, also known as the Japanese littleneck clam, likes to burrow itself into sandy and muddy substrates. They can mostly be found at depths of 10 centimetres. This species is native to Asia but has been introduced all over the world, including the Netherlands. The Manilla clam can reach lengths of up to 7.5 centimetres.